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Chapter 11 : Human Digestive System - Coggle Diagram
Chapter 11 : Human Digestive System
Proteins are used for growth and repair of damaged tissues from animal proteins ( fish , meat , egg white and cheese ) and plant proteins ( soya beans and nuts )
Carbohydrates provide energy from starch ( rice , bread , cereals ) and sugars ( ripe fruit , sweets and soft drinks )
Fats provide twice as much energy as carbohydrates through butter , margarine , cooking oil , peanut and coconut , it also keeps us warm.
These nutrients are too large to be absorbed by our body cells and needs to be broken down by a process called digestion into smaller molecules absorbing the digested food molecules into the bloodstream.
The human digestive system ( alimentary canal ) consists of the mouth , oesophagus , stomach , small intestine , large intestine and anus
Enzymes are produced by the body to speed up the digestion of food
Amylase breaks down carbohydrates to form glucose.
Protease breaks down proteins to form amino acids.
Lipase breaks down fats to form glycerol and fatty acids
Mouth breaks up food into smaller pieces by chewing with teeth to increase the surface area of the food for digestion
The salivary glands in the mouth produces saliva which contains an enzyme known as amylase
Amylase is a carbohydrate that digests starch into maltose
Oesophagus
Food is pushed through the oesophagus by rhythmic contraction and relaxation of muscles along its length
This is known as peristalsis
Stomach have strong muscles that contract rhythmically to churn and further break up food
Proteases digest complex proteins into simpler proteins known as polypeptides
The gastric glands in the stomach produce gastric juice , which contains proteases such as pepsin
Gastric juice also contains hydrochloric acid , which kills microorganisms that enter the digestive system.
Small Intestine is where most digestion takes place
Small intestine produces intestinal juice , which contains enzymes such as amylase , protease and lipase
The pancrease produces pancreatic juice , which also contains enzymes such as amylase , protease and lipase
The liver produces bile , which is stored in the gall bladder.
Bile speeds up the digestion of fats through emulsification
Pancreatic juice and bile are secreted into the small intestine to speed up the digestion of food
Starch --> Maltose --> Glucose , Proteins --> Polypeptides --> Amino Acids , Fats --> Fatty Acids + Glycerol
Large Intestine
Undigested food enters the large intestine
Water and Mineral salts are absorbed from the undigested food.
Faeces are stored temporarily in the rectum before they are passed out of the body